How can I programatically change the content of a block and keep Full HTML formatting

Question

I need to programmatically change the content of a ui configured block. I've partially figured out how to do this, ie:

$ids = \Drupal::entityQuery('block_content')
  ->condition('type', 'custom_block_type')
  ->condition('info', 'Specific block title')
  ->execute();

$my_block = BlockContent::load(array_values($ids)[0]);
$my_block->set('body','<h1>'.$my_processed_string.'</h1>');
$my_block->save();

This does change the content, but when I do this the block loses the Full HTML block format, and the new content in printed out verbatim as html encoded content (ie, the user literally sees '<h1>My altered value</h1>' on the screen). If I go through the ui and change the Text Format field manually to Full HTML, it renders correctly, but that doesn't really accomplish what I need to do.

How can I change the content programatically, without losing the html formatting?

Answer 1

The body field has at least two properties, value and format. To replace the complete field content, you have to use an array:

$my_block->set('body', [[
  'value' => '<h1>' . $my_processed_string . '</h1>',
  'format' => 'full_html',
]]);

Normally you don't need to do this. Set only the value property:

$my_block->body->value = '<h1>' . $my_processed_string . '</h1>';

So that you don't overwrite properties you don't want to change.